Insight into the role of W in amorphous GeTe for phase-change memory

GeTe is a fundamental material for phase-change memory, one of the most promising next-generation data storage devices. Doping GeTe with W has achieved both high writing (crystallization) speed at elevated temperature and long data retention (amorphous stability) at room temperature, which overcame a key challenge for phase-change memory. Yet the effect of W on amorphous GeTe remains ambiguous at atomic and electronic scales. By means of ab initio calculations and molecular dynamics (AIMD) simulations, we shed light on this issue and reveal that W would agglomerate during the melt-quench process and the chemically bonded W cluster plays a key role in tuning the overall phase-change performances of GeTe. Furthermore, the strong W-Ge and W-Te bonds show vital impact on the local structure and crystallization of amorphous GeTe as well. The present work provides valuable clues for advancing the understanding of transition metals doping effects on amorphous phase-change materials, and hence promotes the development of novel phase-change alloys with improved information storage performance.